A systematic review of physical activity and nutritional interventions for the management of normal weight and overweight obesity.

Aims: Normal Weight Obesity (NWO) and Overweight Obesity (OWO) are prevalent conditions, yet knowledge of management is limited. This review aims to assess the effectiveness of physical activity and nutritional interventions in the management of NWO and OWO (together defined as BMI <30 kg/m with raised body fat).

Data Synthesis: Clinical trials including any physical activity or nutritional interventions, published between 2012 and 2022, evaluating body fat change were selected. Seven trials met inclusion criteria, including one single arm intervention, and six RCTs. A high intensity interval training intervention (high risk of bias) had the largest effect on reducing percentage body fat (MD: -6.8%, SE: 0.06). High protein intake interventions were also found to be effective (MD: -2.8%, SE: 0.27, MD: -2.0%, SE: 0.05). These three interventions led to greater increases in fat free mass. Two energy restricted interventions resulted in the highest mean weight loss (MD: -3.10 kg, SD: 0.87 (intervention only), MD: -2.90 kg, SE: 0.06), but also loss of fat free mass, resulting in low reductions in percentage body fat (MD: -1.10%, SD: 0.57 (intervention only), MD: -0.8%, SE 0.30). There was considerable heterogeneity between studies.

Conclusions: There are physical activity and nutritional interventions that could be efficacious for the management of NWO and OWO. However, there was considerable heterogeneity between studies. The most promising nutritional intervention is high protein intake and the least is energy restriction (without increased protein intake). More high-quality trials are needed to evaluate interventions, and to determine the best tools to measure adiposity.